1. Field
A scroll compressor is disclosed herein.
2. Background
A scroll compressor is a compressor in which a fixed scroll is fixed to or in an inner space of a casing, and a pair of compression spaces including a suction chamber, an intermediate pressure chamber, and a discharge chamber are formed between a fixed wrap of the fixed scroll and an orbiting wrap of an orbiting scroll while the orbiting scroll engaged with the fixed scroll performs an orbiting movement. The scroll compressor is widely used to compress refrigerant in an air conditioning unit, for example, due to an advantage of being capable of obtaining a stable torque as suction, compression, and discharge strokes are smoothly carried out, as well as obtaining a relatively higher compression ratio compared to other types of compressors. In recent years, high-efficiency scroll compressors, in which an eccentric load is reduced to have an operation speed of above 180 Hz have been developed.
FIG. 1 is a longitudinal cross-sectional view illustrating an example of a high-pressure compressor (hereinafter, abbreviated as a “scroll compressor”) in the related art. As illustrated in the drawing, according to a scroll compressor in the related art, a drive motor 20 to generate a rotational force is provided in an inner space 11 of a sealed casing 10, and a mainframe 30 is provided at an upper side of the drive motor 20.
A fixed scroll 40 is provided in a fixed manner on an upper surface of the mainframe 30, and an orbiting scroll 50 is provided in an orbital manner between the mainframe 30 and the fixed scroll 40. The orbiting scroll 50 is coupled to a rotational shaft 60 coupled to a rotor 22 of the drive motor 20.
The orbiting scroll 50 is formed with an orbiting wrap 52 engaged with a fixed wrap 43 of the fixed scroll 40 to form a pair of consecutively moving compression spaces (P). The pair of compression space (P) is consecutively formed with a suction chamber, an intermediate pressure chamber, and a discharge chamber, and the intermediate pressure chamber is consecutively formed with several phases.
Further, an Oldham ring 70 that prevents a rotational movement of the orbiting scroll 50 is provided between the fixed scroll 40 and the orbiting scroll 50. The Oldham ring 70 is formed of an aluminum material.
As illustrated in FIG. 2, the Oldham ring 70 includes a ring portion or ring 71 formed in an annular shape, and a plurality of key portions or keys 75 formed in a protruding manner on both axial-directional lateral surfaces of the ring portion 71. The ring portion 71 is formed in a ring shape, and the entire both axial-directional lateral surfaces excluding the key portion 75 are formed in a flat shape. However, according to circumstances, thrust surfaces may be formed in a protruding manner by a predetermined height in a stepwise manner on both axial-directional lateral surfaces, respectively, around the key portion 75.
The key portion 75 may include a first key portion or key 76 slidably inserted into a key groove 35 of the mainframe 30 and a second key portion or key 78 slidably inserted into a key groove 55 of the orbiting scroll 50.
The first key portion 76 is formed on one axial-directional lateral surface of the ring portion 71 space at intervals of 180 degrees along a circumferential direction, and the second key portion 78 is formed on the other axial-direction lateral surface of the ring portion 71 spaced at intervals of 180 degrees along the circumferential direction. The first key portion 76 and second key portion 78 are alternately formed at intervals of 90 degrees along the circumferential direction when projected onto a plane.
An oil separator 90 that communicates with a discharge pipe 16 to separate oil from refrigerant discharged from the casing 10 is provided at one side of the casing 10, an oil return pipe 91 that communicates with the inner space 11 of the casing 10 filled with oil to return the separated oil to the casing 10 is connected to a lower end of the oil separator 90, and a refrigerant pipe 92 configured to guide refrigerant from which oil has been separated to a condenser of a cooling cycle is connected to at an upper end of the oil separator 90.
On the drawing, reference numerals 15, 21, 41, 42, 44, 45, 51, 53, 61, 62, 65, and 80 are a suction pipe, a stator, an end plate portion or end plate of the fixed scroll 40, a side wall portion or side wall of the fixed scroll 40, a suction port, a discharge port, an end plate portion or end plate of the orbiting scroll 50, a boss portion or boss, an oil passage, a boss portion insertion groove, a balance weight, and a sub-frame, respectively.
According to the foregoing scroll compressor in the related art, when power is applied to the drive motor 20 to generate a rotational force, the rotational shaft 60 transfers the rotational force of the drive motor 20 to the orbiting scroll 50. Then, the orbiting scroll 50 forms the pair of compression spaces (P) between the orbiting scroll 50 and the fixed scroll 40 while performing an orbiting movement with respect to the fixed scroll 40 by the Oldham ring 70 to suck, compress, and discharge refrigerant.
Though the orbiting scroll 50 receives a rotational force in a circumferential direction by the rotational shaft 60, wear due to a concentrated load may be generated between one lateral surface of the first key portion 76 and the second key portion 78 and one lateral surface of each key groove 35, 55, as the first key portion 76 and the second key portion 78 of the Oldham ring 70 are slidably inserted in a radial direction into the key groove 35 of the mainframe 30 and the key groove 55 of the orbiting scroll 50. However, the first key portion 76 of the Oldham ring 70 and the key groove 35 of the orbiting scroll 50 may be formed in a direction perpendicular to the second key portion 78 of the Oldham ring 70 and the key groove 55 of the orbiting scroll 50, thereby suppressing wear between each key and key groove, as well as allowing the orbiting scroll 50 to perform the orbiting movement with respect to the mainframe 30. On the drawing, reference numerals t1 and t2 are a thickness of the ring portion and a thickness between both thrust surfaces.
However, the foregoing scroll compressor in the related art has a problem of generating severe wear on the Oldham ring 70 as both the orbiting scroll 50 and Oldham ring 70 are formed of an aluminum material. Typically, in a case in which two members being slidably brought into contact with each other are formed of the same type material, it causes relatively high wear compared to a case of being formed of different types of materials. In consideration of this, when the Oldham ring 70 is formed of a material with a high hardness, such as cast iron, for example, a weight of the Oldham ring 70 is increased to increase an eccentric load due to a centrifugal force, thereby causing a problem of increasing vibration noise of the compressor.